Process for activation of titanium and vanadium catalysts useful in ethylene polymerization

ABSTRACT

A process for activating a titanium or vanadium compound and producing polyethylene comprising (i) dissolving a divalent magnesium halide and a Lewis acid having the formula R m  A1X n  or R m  BX n  wherein R is an alkyl or aromatic radical, each radical having 1 to 12 carbon atoms and each R being alike or different; X is a halogen atom; m is an integer from 0 to 3; n is an integer from 0 to 3; and m+n equals 3, in an excess of electron donor compound selected from the group consisting of alkyl esters of alkyl and aromatic carboxylic acids and alkyl and cycloalkyl ethers, each compound having 2 to 12 carbon atoms, in such a manner that a magnesium halide/Lewis acid/electron donor complex is formed; (ii) separating the complex from excess electron donor compound; and (iii) introducing (a) the complex, the titanium or vanadium compound, and a hydrocarbyl aluminum compound and (b) ethylene into a reactor in such a manner that the titanium or vanadium compound is activated and polyethylene is produced.

This application is a Division of prior U.S. application Ser. No.833,148, filing date 2/27/86, and now Pat. No. 4,670,526.

TECHNICAL FIELD

This invention relates to a process for the activation of an ethylenepolymerization catalyst, and an activator therefor.

BACKGROUND ART

A typical ethylene polymerization catalyst is prepared by forming aprecursor from a magnesium compound, a titanium compound, and anelectron donor compound; diluting the precursor with an inert carriermaterial; and activating the precursor by introducing an organoaluminumcompound. The process is described in U.S. Pat. Nos. 4,302,565;4,302,566; and 4,303,771, incorporated by reference herein. Themagnesium and titanium compounds are dissolved in the electron donorcompound (solvent) at a temperature ranging from ambient to below theboiling point of the electron donor. The order of addition to theelectron donor compound is not important to the result, i.e., one or theother of the magnesium and titanium compounds can be added first or theycan be added together. The dissolution in the electron donor compoundcan be enhanced by slurrying or refluxing. After the magnesium andtitanium compounds are dissolved, the resulting product is isolated bycrystallization or precipitation with a hydrocarbon such as hexane,isopentane, or benzene. The crystallized or precipitated product isdried and recovered as fine, free-flowing particles. Themagnesium/titanium based composition is then mixed with, or impregnatedinto, an inert carrier material. The carrier is generally a solid,particulate, porous material such as silica.

In order for the magnesium/titanium based composition to be useful as apolymerization catalyst, it must be activated with a compound capable oftransforming the magnesium/titanium atoms to a state which will effectthe desired polymerization reaction. Activation is accomplished by theaddition of an organoaluminum compound. Partial activation, if desired,is effected outside of the polymerization reactor by introducing thecatalyst composition and the organoaluminum into a solvent. Completeactivation is then carried out in the reactor as described in U.S. Pat.No. 4,383,095, incorporated by reference herein.

While the magnesium/titanium based catalyst compositions have proved tobe satisfactory ethylene polymerization catalysts, there is a continuingeffort to improve on the catalysis aspect of ethylene polymerizationand, more particularly, to improve the technique for catalystactivation.

DISCLOSURE OF THE INVENTION

An object of this invention, therefore, is to provide a process for theactivation of known ethylene polymerization catalysts, such as titaniumor vanadium compounds, whereby an activated catalyst is prepared muchmore rapidly and simply than by following the route to the activatedmagnesium/titanium based catalyst composition heretofore discussed.

Other objects and advantages will become apparent hereafter.

According to the present invention, a process for activating a titaniumor vanadium compound and producing polyethylene has been discoveredcomprising (i) dissolving a divalent magnesium halide and a Lewis acidhaving the formula R_(m) AlX_(n) or R_(m) BX_(n) wherein R is an alkylor aromatic radical, each radical having 1 to 12 carbon atoms and each Rbeing alike or different; X is a halogen atom; m is an integer from 0 to3; and m+n equals 3, in an excess of electron donor compound selectedfrom the group consisting of alkyl esters of alkyl and aromaticcarboxylic acids and alkyl and cycloalkyl ethers, such compound having 2to 12 carbon atoms, in such a manner that a magnesium halide/Lewisacid/electron donor complex is formed; (ii) separating the complex fromexcess electron donor compound; and (iii) introducing (a) the complex,the titanium or vanadium compound, and a hydrocarbyl aluminum compoundand (b) ethylene into a reactor in such a manner that the titanium orvanadium compound is activated and polyethylene is produced.

DETAILED DESCRIPTION

Titanium or vanadium compounds of interest here are commonly used ascatalyst components in the polymerization of ethylene. Typical titaniumcompounds have the formula Ti(OR)_(n) X_(4-n) wherein R is a hydrocarbylgroup having 1 to 14 carbon atoms or a COR' radical wherein R' is ahydrocarbyl group having 1 to 14 carbon atoms; X is a halide radical;and n is an integer from 0 to 4. Examples of titanium compounds areTiCl₄ ; TiBr₄ ; TiI₄ ; Ti(OCH₃)Cl₃ ; Ti(OC₆ H₅)Cl₃ ; TI(OCOCH₃)Cl₃ ;Ti(OCOC₆ H₅)Cl₃ ; Ti(OC₂ H₅)Cl₃ ; Ti(OC₂ H₅)₂ Cl₂ ; Ti(OC₃ H₇)₂ Cl₂ ;Ti(OC₂ H₅)₃ Cl; Ti(OC₆ H₅)₃ Cl, Ti(OC₂ H₅)₄ ; Ti(OC₃ H₇)₄ ; Ti(OC₄ H₉)₄; Ti(OC₆ H₁₃)₄, Ti(OC₆ H₁₁)₄ ; Ti(OC₈ H₁₇)₄ ; Ti(OCH₂ (C₂ H₅)CHC₄ H₉ )₄; Ti(OC₉ H₁₉)₄ ; Ti[OC₆ H₃ (CH₃)₂ ]₄ ; Ti(OCH₃)₂ (OC₄ H₉)₂ ; Ti(OC₃ H₇)₃(OC₄ H₉); Ti(OC₂ H₅)₂ (OC₄ H₉)₂ ; Ti(OC₂ H₄ OCH₃)₄ ; and Ti(OC₂ H₄ Cl)₄.Examples of vanadium compounds are VCl₄, VCl₃, VOCl₃, triisobutylvanadate, and vanadium tris-acetyl acetonate. Other suitable vanadiumcompounds are mentioned in U.S. Pat. Nos. 3,956,255 and 4,370,455, bothincorporated by reference herein.

The electron donor solvents used in the process are organic compounds,liquid at temperatures in the range of about 0° C. to about 200° C., inwhich the magnesium halide and defined Lewis acids are soluble. Theelectron donor solvents are also known as Lewis bases.

The electron donor compounds are selected from the group consisting ofalkyl esters of alkyl and aromatic carboxylic acids and alkyl andcycloalkyl ethers, each compound having 2 to 12 carbon atoms. Amongthese electron donor compounds the preferable ones are alkyl esters ofsaturated alkyl carboxylic acids having 1 to 4 carbon atoms; alkylesters of aromatic carboxylic acids having 7 or 8 carbon atoms; alkylethers having 2 to 8 carbon atoms, preferably 4 or 5 carbon atoms; andcycloalkyl ethers having 4 or 5 carbon atoms; preferably mono- ordi-ethers having 4 carbon atoms. The most preferred of these electrondonor compounds include methyl formate, ethyl acetate, butyl acetate,ethyl ether, tetrahydrofuran, and dioxane. Other examples of electrondonor compounds are di-n-propyl ether, dibutyl ether, ethyl formate,methyl acetate, ethyl anisate, ethylene carbonate, tetrahydropyran, andethyl propionate.

The divalent magnesium halide can be represented by the formula

    MgX.sub.2

wherein X is selected from the group consisting of Cl, Br, and I.

Suitable magnesium compounds include MgCl₂, MgBr₂, and MgI₂. AnhydrousMgCl₂ is particularly preferred.

The Lewis acids are, as noted above, those having the formula R_(m)AlX_(n) or R_(m) BX_(n) wherein R is an alkyl or aromatic radical, eachradical having 1 to 12 carbon atoms and each R being alike or different;X is a halogen atom; M is an integer from 0 to 3; n is an integer from 0to 3; and m+n equals 3. Examples of alkyl radicals are: methyl, ethyl,propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl,hexyl, 2-methylpentyl, heptyl, octyl, isooctyl, 2-ethylhexyl,5,5-dimethylhexyl, nonyl, decyl, isodecyl, undecyl, and dodecyl. Exampleof aromatic radicals are: phenyl, phenethyl, methoxyphenyl, benzyl,tolyl, xylyl, naphthyl, naphthal, and methylnaphthyl. Examples ofhalogens are chlorine, bromine, and iodine.

Preferred Lewis acids are AlCl₃, C₂ H₅ AlCl₂, (C₂ H₅)₂ AlCl, (C₂ H₅)₃Al, and BCl₃. Other examples of suitable Lewis acids are triisobutylaluminum, tributylaluminum, dibutylaluminum chloride, diethylaluminumbromide, propylaluminum dichloride, butylaluminum dibromide, Al(C₆H₁₃)₃, Al(C₈ H₁₇)₃, trimethylaluminum, diisobutylaluminum chloride,isobutylaluminum dichloride, diethylaluminum methoxide, diethylaluminumethoxide, dimethylaluminum chloride, and methylaluminum dichloride.

The magnesium halide/Lewis acid/electron donor complex, which may alsobe referred to as an adduct or solvated adduct, is formed when thedivalent magnesium halide is dissolved in an electron donor togetherwith a Lewis acid at a temperature in the range of about 0° C. to about200° C. The molar ratio of magnesium halide to Lewis acid can be in therange of about 0.1 mole to about 4 moles of magnesium halide to one moleof Lewis acid and is preferably in the range of about 0.5 mole to about2 moles of magnesium halide to one mole of Lewis acid. An excess ofelectron donor compound, i.e., a number of moles of electron donorcompound at least about 15 times greater than the total number of molesof magnesium halide and Lewis acid combined, provides a sufficientnumber of moles of electron donor to yield the complex. Whileatmospheric pressure is generally used, pressure is not considered asignificant factor. These solvated adducts can be isolated byevaporation of excess solvent or by slow crystallization of the adductafter partial concentration of the solvent. Preferred complexes arederived from MgCl₂ and the Lewis acids AlCl₃, C₂ H₅ AlCl₂, (C₂ H₅)₂AlCl, (C₂ H₅)₃ Al, and BCl₃. These complexes are as follows:

MgCl₂.2AlCl₃.nTHF

MgCl₂.2EADC.nTHF

MgCl₂.EADC.nTHF

2MgCl₂.TEAL.nTHF

MgCl₂.2AlCl₃.nEtOAC

MgCl₂.2BCl₃.6EtOAC

MgCl₂.2EADC.nEtOAC

wherein n can be an integer from 1 to 13 and is preferably an integerfrom 5 to 12. The integer represents the number of moles of electrondonor compound.

The following acronyms are used above and throughout this specification:

EADC=ethylaluminum dichloride

THF=tetrahydrofuran

TEAL=triethylaluminum

EtOAC=ethyl acetate

DEAC=diethylaluminum chloride

Analyses of six of the complexes are set forth in Table I.

                  TABLE I                                                         ______________________________________                                                     Analyses   Analyzed Molar                                                      (weight %)                                                                              Stoichiometries                                       Complex        Mg     Al     B    Mg   Al   B                                 ______________________________________                                        MgCl.sub.2.2AlCl.sub.3.nTHF                                                                  2.14   5.46   --   1    2.27 --                                MgCl.sub.2.2EADC.nTHF                                                                        2.74   6.71   --   1    2.20 --                                MgCl.sub.2.EADC.nTHF                                                                         4.44   5.25   --   1    1.06 --                                2MgCl.sub.2.TEAL.nTHF                                                                        6.48   3.56   --   2.02 1    --                                MgCl.sub.2.2BCl.sub.3.6EtOAC                                                                 3.01   --     2.79 1    --   2.04                              MgCl.sub.2.2EADC.nEtOAC                                                                      2.42   5.57   --   1    2.07 --                                ______________________________________                                    

The family of subject complexes is found to activate titanium orvanadium compounds, particularly titanium tetrachloride, in the presenceof a hydrocarbyl aluminum compound as a cocatalyst, in ethylene gasphase or slurry polymerization reactions. A catalyst, prepared byslurrying one of these complexes with titanium tetrachloride in hexane(or another inert hydrocarbon solvent), followed by washing with excesshexane and drying under reduced pressure possesses excellent activity inhexane polymerization reactions employing triethyl aluminum as acocatalyst.

The hydrocarbyl aluminum cocatalyst can be represented by the formula R₃Al wherein each R is an alkyl, cycloalkyl, aryl, or hydride radical; atleast one R is a hydrocarbyl radical; two or three R radicals can bejoined in a cyclic radical forming a heterocyclic structure; each R canbe alike or different; and each R, which is a hydrocarbyl radical, has 1to 20 carbon atoms, and preferably 1 to 10 carbon atoms. Further, eachalkyl radical can be straight or branched chain and such hydrocarbylradical can be a mixed radical, i.e., the radical can contain alkyl,aryl, and/or cycloalkyl groups. Examples of suitable radicals are:methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl,neopentyl, hexyl, 2-methylpentyl, heptyl, octyl, isooctyl, 2-ethylhexyl,5,5-dimethylhexyl, nonyl, decyl, isodecyl, undecyl, dodecyl, phenyl,phenethyl, methoxyphenyl, benzyl, tolyl, xylyl, naphthyl, naphthal,methylnaphthyl, cycohexyl, cycloheptyl, and cyclooctyl.

Examples of hydrocarbyl aluminum compounds are as follows:triisobutylaluminum, trihexylaluminum, di-isobutylaluminum hydride,dihexylaluminum hydride, isobutylaluminum dihydride, hexylaluminumdihydride, di-isobutylhexylaluminum, isobutyl dihexylaluminum,trimethylaluminum, triethylaluminum, tripropylaluminum,triisopropylaluminum, tri-n-butylaluminum, trioctylaluminum,tridecylaluminum, tridodecylaluminum, tribenzylaluminum,triphenylaluminum, trinaphthylaluminum, and tritolylaluminum. Thepreferred hydrocarbyl aluminums are triethylaluminum,triisobutylaluminum, trihexylaluminum, di-isobutylaluminum hydride, anddihexylaluminum hydride.

These complexes also activate titanium or vanadium compounds when thecomplex is first impregnated on a silica support. The purpose of theimpregnation is to produce polymers of preferred shape and bulk density.To achieve this end, the magnesium halide and Lewis acid are dissolvedin the electron donor solvent and slurried with the silica support. Theexcess solvent is then removed by purging or evaporation under reducedpressure. The resulting impregnated complexes are slurried with, forexample, the tetravalent titanium compound in hexane, followed bywashing with excess hexane and drying, as above. These impregnatedcatalysts are also found to be active with triethyl aluminum as acocatalyst. The result of the copolymerization is not only high catalystactivity, but high bulk density as well.

Further, it is found that the solubility of the divalent magnesiumhalide in the electron donor solvent is increased by the presence of thedefined Lewis acid, e.g., the degree of solubility of MgCl₂ intetrahydrofuran is increased 100 percent by using a 0.6 molar solutionof triethylaluminum in tetrahydrofuran.

Conductivity experiments measure the ability of a solution to carry acharge across a fixed path between two electrodes. If the bondinginteraction between the magnesium halide and the Lewis acid in theelectron donor solvent is ionic then a significant increase inconductivity over each component alone in the electron donor solventshould occur. The results of a series of conductivity experimentsindicate just such an increase and it is therefore concluded that thesubject complex is ionic in character. Since the conductive capacity isreached almost immediately upon mixing the components, there apparentlyis no kinetic barrier to interaction of the magnesium halide and Lewisacid in the electron donor solvent.

Impregnation of subject complex into, for example, silica prior to itsuse in titanium or vanadium compound activation is desirable to provideimproved particle morphology. The impregnation is accomplished by mixingthe complex and silica gel in the electron donor solvent followed bysolvent removal under reduced pressure. Ethylene polymerizationreactions are run by either slurrying the silica gel supported complexwith the tetravalent titanium compound or isolating the impregnatedsilica gel after treatment with the tetravalent titanium compound, andthen using the slurry or isolated precursor in the polymerizationreaction. It is found that the levels of catalyst activity, resinproperties, and bulk densities compare favorably with catalystsexemplified by the reaction product of magnesium dichloride/titaniumtetrachloride/tetrahydrofuran and triethyl aluminum.

The invention is illustrated by the following examples:

Complexes are formed when magnesium dichloride and a defined Lewis acidare dissolved in an excess of electron donor solvent. The solvatedcomplex is isolated by evaporation of excess solvent or slowcrystallization after partial evaporation of the solvent. The complex iseither (1) slurried with titanium tetrachloride in hexane to form aprecursor, which is then isolated, or (2) slurried with titaniumtetrachloride in hexane just prior to introduction into thepolymerization reactor.

EXAMPLE 1

The complex MgCl₂ /2EADC/THF is prepared as follows: to a flask is added1.93 grams (15 millimoles) of ethylaluminum dichloride. After chillingto 0° C., one cubic centimeter of THF is added and the solid dissolvesimmediately. After warming to room temperature, 9 cubic centimeters of0.51 molar MgCl₂ in THF is added and a white precipitate formsimmediately. The mixture is warmed to 40° C. and all of the soliddissolves. Upon cooling to ambient temperature, the precipitate reforms.The mixture is cooled to 0° C. and the mother liquor is decanted away.The residue is then washed with cold THF and dried under high vacuum.

Analysis of complex: 6.71% by weight aluminum; 2.74% by weight magnesium

Proton nuclear magnetic resonance (CH₂ Cl₂, chemical shift in parts permillion): minus 0.15 quartet; 0.83 triplet; 1.80 multiplet, 3.90multiplet.

This spectrum is uniquely different from any of the starting materials.

EXAMPLE 2

The complex MgCl₂ /EADC/THF is prepared as follows: to a flask is added1.94 grams (15 millimoles) of ethyl aluminum dichloride. After coolingthe flask to 0° C., 13.3 cubic centimeters of 0.52 molar MgCl₂ (6.9millimoles) in THF is added. The solution is concentrated to 5 cubiccentimeters and a crop of crystals is collected by decanting away themother liquor. The mother liquor is allowed to stand and a second cropof crystals is collected.

Analysis of complex (second crop of crystals): 5.25% by weight aluminum;4.44% by weight magnesium

Infrared spectrum (Nujol mull; cm⁻¹), ether absorptions only: 1025,1015, 875; 862; 848.

As in example 1, this spectrum is uniquely different from any of thestarting materials.

EXAMPLE 3

The complex MgCl₂ /2EADC/EtOAC is prepared as follows: to a flask isadded 1.9 grams (15 millimoles) of ethyl aluminum dichloride with 8cubic centimeters of 0.52 molar MgCl₂ in EtOAC. A precipitate formsimmediately. The mixture is warmed and allowed to cool slowly. A whitesolid forms and is collected by decanting away the mother liquor. Theremaining solid is cooled and washed two times with cold EtOAC.

Analysis: 2.42% by weight magnesium; 5.57% by weight aluminum

H¹ NMR (nuclear magnetic resonance) spectrum (CH₂ Cl₂, chemical shift inparts per million): minus 0.05 quartet; 0.95 triplet; 1.17 triplet; 2.14singlet; 4.14 quartet.

This spectrum is also uniquely different from any of the startingmaterials.

EXAMPLE 4

The complex MgCl₂ /2BCl₃ /EtOAc is prepared as follows: to a flask areadded equal volumes of 0.13 molar MgCl₂ and BCl₃ solutions in ethylacetate. A white precipitate forms immediately and is isolated byfiltration.

Analysis: 3.01% by weight magnesium; 2.79% by weight boron; 34.7% byweight chlorine

EXAMPLES 5 TO 8

The catalyst in examples 5 to 8 is prepared by isolating an adductformed by slurrying the complex with an excess of TiCl₄ in hexane. Thetitanium derivative is isolated by decanting away the hexane solutionand washing the residue with excess hexane. Additional steps,conditions, and results will be found below and in Table II.

EXAMPLE 9

The complex is slurried with 7 milligrams of TiCl₄ just prior toaddition to the polymerization reaction. Additional steps, conditions,and results will be found below and in Table II.

EXAMPLES 10 AND 11

(a) To a flask is added 12.67 grams of silica, which has been driedunder a nitrogen purge at 800° C. To the silica is added 75 cubiccentimeters of THF followed by 5.9 cubic centimeters of 1.5 molar EADCin hexane (8.85 millimoles). Next, 8.5 cubic centimeters of 0.52 molarMgCl₂ in THF is added. After stirring, the solvent is removed underreduced pressure.

(b) To a flask is charged 5.48 grams of the supported complex with 20cubic centimeters of hexane. To this is added 0.35 millimoles of TiCl₄per gram of supported complex. The mixture is stirred, allowed tosettle, and the solvent is decanted away. The solid is washed threetimes with hexane, then dried under vacuum. Additional steps,conditions, and results will be found below and in Table II.

EXAMPLES 12 AND 13

Example 10 is repeated except that DEAC is substituted for EADC.Additional steps, conditions, and results will be found below and inTable II.

Each catalyst of examples 5 to 13 and TEAL as a cocatalyst are added toa reaction vessel containing 20 cubic centimeters of 1-hexene. Ethyleneis introduced at an initial pressure of 0.89 megaPascal. Hydrogen isalso introduced at 0.14 megaPascal. The reaction temperature is 85° C.

Table II sets forth the following conditions and results:

1. The isolated magnesium halide/Lewis acid/electron donor complex.Milligrams of catalyst are set forth in parentheses. In examples 10 to13, this weight includes the support.

2. The method of titanium addition, i.e., (1) or (2) described above. Inmethod (2), the milligrams of titanium added in examples 9, 11, and 13are 7, 6.9, and 6.9, respectively.

3. The percentage of titanium in the catalyst.

4. Triethylaluminum is used as a cocatalyst. The mole ratio oftriethylaluminum to titanium is given.

5. The activity of the catalyst in kilograms of polyethylene permillimole of titanium per hour at an ethylene pressure of onemegaPascal.

6. Melt index: ASTM D-1238, Condition E. Measured at 190° C. andreported as grams per 10 minutes.

7. Melt flow ratio: Ratio of Flow Index to Melt Index. Flow Index: ASTMD-1238, Condition F. Measured at 10 times the weight used in the meltindex test above.

8. Polymer density: ASTM D-1505 procedure is followed for polymershaving a density of less than 0.940 gram per cubic centimeter and amodified procedure is used for polymers having a density equal to orgreater than 0.940 gram per cubic centimeter. For the low densitypolymers, a plaque is made and conditioned for one hour at 100° C. toapproach equilibrium crystallinity. For the high density polymers, theplaque is conditioned for one hour at 120° C. to approach equilibriumcrystallinity, and is then quickly cooled to room temperature.Measurement for density is then made in a density gradient column anddensity values are reported as grams per cubic centimeter.

9. Polymer bulk density: ASTM D-1895, Method B. The resin is poured viaa 3/8 inch diameter funnel into a 400 milliliter graduated cylinder tothe 400 milliliter line without shaking the cylinder, and weighed bydifference. Density values are reported as kilograms per cubic meter.

                                      TABLE II                                    __________________________________________________________________________                     Method     TEAL/                                                                              Activity    Melt                                                                              Polymer                                       of Ti Percent                                                                            Ti Mole                                                                            kg/mmTi/                                                                              Melt                                                                              Flow                                                                              Density                                                                             Polymer Bulk           Complex          Addition                                                                            Ti   Ratio                                                                              hr/mPaC.sub.2 H.sub.4                                                                 Index                                                                             Ratio                                                                             g/cc  Density                __________________________________________________________________________                                                           kg/m.sup.3              5. MgCl.sub.2.2EADC.THF (27.9)                                                                (1)   4.44 40   7.59    2.1 26  0.9455                                                                              --                      6. MgCl.sub.2.EADC.THF (18.3)                                                                 (1)   7.53 40   4.90    0.83                                                                              24  0.9428                                                                              --                      7. MgCl.sub.2.2AlCl.sub.3.THF (18.7)                                                          (1)   4.81 40   2.00    --  --  0.9436                                                                              --                      8. 2MgCl.sub.2.TEAL.THF (26.1)                                                                (1)   4.85 40   4.92    0.84                                                                              24  0.9442                                                                              --                      9. MgCl.sub.2.2EADC.EtOAC (50.9)                                                              (2)   --   40   1.49    --  --  --    --                     10. MgCl.sub.2.2EADC.THF (207)                                                                 (1)   1.20 40   2.85    2.2 26  0.9493                                                                              290                    11. MgCl.sub.2.2EADC.THF (202)                                                                 (2)   --   40   3.15    0.91                                                                              25  0.9452                                                                              290                    12. MgCl.sub.2.2DEAC.THF (210)                                                                 (1)   1.47 40   1.86    1.6 25  0.9507                                                                              290                    13. MgCl.sub.2.2DEAC.THF (198)                                                                 (2)   --   40   2.67    0.93                                                                              26  0.9485                                                                              290                    __________________________________________________________________________

We claim:
 1. A complex consisting essentially of the reaction product ofa divalent magnesium halide; a Lewis acid having the formula R_(m)AlX_(n) or R_(m) BX_(n) wherein R is an alkyl or aromatic radical, eachradical having 1 to 12 carbon atoms and each R being alike or different;X is a halogen atom; m is an integer from 0 to 3; n is an integer from 0to 3; and m+n equals 3; and an electron donor compound selected from thegroup consisting of alkyl esters of alkyl and aromatic carboxylic acidsand alkyl and cycloalkyl ethers, each compound having 2 to 12 carbonatoms wherein the ratio of magnesium halide to Lewis acid is in therange of about 0.1 mole to about 4 moles of magnesium halide per mole ofLewis acid, said reaction product being formed on dissolution of themagnesium halide and Lewis acid in the electron donor compound.
 2. Thecomplex defined in claim 1 wherein the halide is divalent magnesiumchloride.
 3. The complex defined in claim 1 wherein the Lewis acid isselected from the group consisting of AlCl₃, C₂ H₅ AlCl₂, (C₂ H₅)₂ AlCl,(C₂ H₅)₃ Al, and BCl₃.
 4. The complex defined in claim 3 wherein theelectron donor compound is selected from the group consisting of alkylesters of saturated alkyl carboxylic acids having 1 to 4 carbon atoms;alkyl esters of aromatic carboxylic acids having 7 or 8 carbon atoms;alkyl ethers having 2 to 8 carbon atoms; and cycloalkyl ethers having 4or 5 carbon atoms.
 5. The complex defined in claim 4 wherein theelectron donor compound is selected from the group consisting of methylformate, ethyl acetate, butyl acetate, ethyl ether, tetrahydrofuran, anddioxane.
 6. The complex defined in claim 5 wherein the ratio ofmagnesium halide to Lewis acid is in the range of about 0.5 mole toabout 2 moles of magnesium halide per mole of Lewis acid.